RichFaces 4.3.x Tip of the Day: Complex RichFaces Data Tables

Introduction

I have been working on JSF tables for the various projects I have been involved with over the years. Starting in 2012, I began looking at RichFaces <rich:dataTable /> for some projects at my day job. The research into how to handle a number of complex situations has been enlightening to say the least.

The table is the most complex component in HTML. It is seemingly boundless in its extensibility. You can have multi-column headers that span multiple rows, you can multi-row cells, or multi-column cells. Tables can be displayed left-to-right, or right-to-left, top-to-bottom and vice-versa. As a result, when developing components for JSF, or any component framework, decisions must be made on how to generate them.

A couple of the component frameworks like PrimeFaces, and RichFaces allow developers to create more complex tables with more ease. However there are limitations with each of these frameworks. We trade flexibility for consistency, and this is fine in most cases.

The demonstration code in this post is about getting some of the flexibility back, or taking advantage of the flexibility that comes with a framework like RichFaces. We will gain the flexibility back, but it is a function of complexity. The examples will show you techniques for doing the "same thing" in multiple ways. For example, sorting can be done on the server, client, or a combination of both.

The question is where we put the complex bits. The answer to that question depends on you as a developer. You need to examine the problem domain, and understand the limits to the techniques presented.

Solutions

Please let me confess something. I like building HTML objects programmatically. There I said it. In this case I am trading the ease of development for flexibility. The solutions below will demonstrate the different techniques for accomplishing the same functionality. Please examine the code carefully before discounting it. I spent a lot of time playing with it to make it look simple.

The code for this project was developed using NetBeans and Apache Maven. The code was tested on GlassFish 3.1.2.2 and 4.0. It should work on other application servers, but I have not tested it on other servers. This project assumes you are using NetBeans which includes a sample database that these examples require. If you are not using NetBeans, you will need to create your own database with sample data to display some of the tables.

The code can be downloaded from Bitbucket at the link below, or in the references section at the end of the post.

richfaces-tables-poc

Dynamic Data Table with Sorting

Dynamic Table with Sorting

This example uses the binding attribute of the <rich:dataTable /> to bind our table to a CDI @ManagedBean. The bean is responsible for generating the table programmatically, and returning it back to the page. The data is sortable by column.
As you can see the page is very simple. In fact, most of the page is plumbing and navigation. The <rich:dataTable /> is the smallest part of the page. The code to generate the table is much more complex.
As you can see we have traded simplicity in the page for complexity in the @ManagedBean. If you are satisfied with this technique, lets take a look at another one.

Dynamic Data Table with Sorting Revisited

Dynamic Table

This table uses the same dynamic binding as the example above on the JSF page, but uses helper utilities to create JSF components dynamically from a library that I have written. It is a separate project that you can download (Please see references). This reduces the chances for errors creating common components, but it is still a lot of code. To check our sorting, I have made a "random" data generator for the table data for the code to sort.
The more simplified code in the @ManagedBean is shown below.
The code above was written before I added more functionality to my jsf-utils project. The new methods would shorten this considerably, but it would still be fairly complex.

Dynamic Table using JSP/JSTL Tags with JSF

JSF/JSTL Dynamic Table

Let me start this example with a warning. If you are using JSP/JSTL tags in your JSF pages, you may encounter very bad behavior. This technique should only be used as a last resort. I will not labor a point. If you don't understand why this is a bad idea, take a look at this post for links: JSF 2.x Tip of the Day: Great Blog Posts Explaining JSTL vs. JSF.
In this example, I will generate the rows and columns using <c:forEach />. This transfers a lot of the complexity to the page and away from the @ManagedBean. Since we are using <c:forEach />, our mechanism for sorting has to change. I used Query jquery.tablesorter.js to allow sorting of the headers.
As you can see we have much simpler code in the page bean. It looks like what you would expect for a normal JSF data table.

Complex Data Table Design

Complex Table Design

This table has a lot of really cool features, but the code is complex in the page, and the page bean is relatively simple.

Conclusion

RichFaces supports complex table designs, and produces nice results. The amount of work required to create dynamic data tables depends on the technique chosen, and limitations on the data being presented. There is no "one good way" to create data tables. Suffice to say that the easiest path should be chosen.

References

• richfaces-tables-poc Apache Maven project
• jsf-utils
• JSF 2.x Tip of the Day: Great Blog Posts Explaining JSTL vs. JSF
• RichFaces
• NetBeans IDE

Dr. Dobbs - Making Large Classes Small (In 5 Not-So-Easy Steps)

Image via Wikipedia

This editorial by Andrew Binstock is really good. As a developer, we often forget to code our applications in a way to focus on the basics for maintenance, extension, usability (re-usability too), and testing. Andrew talks about these in a succinct article which I have linked to below. It is funny how often we forget these items in the "heat of battle" only to rediscover our sins later when trying to maintain our code.

Take a read on the article it is short and sweet.

Making Large Classes Small (In 5 Not-So-Easy Steps)

Release It! Review

I just completed reading Release It! by Michael T. Nyggard (Pragmatic Bookshelf 2007). It is part of The Pragmatic Programmers series. I have read the book cover to cover twice. At first, I thought that the book was just another book on how to manage projects. So What! The ideas presented in the book were common sense. I have been doing these same things for many years.

Then one day I was working on a project, and was trying to figure out how to handle a problem. I remembered what I read in Release It! about the topic. I grabbed the book off the bookshelf and looked it up; logging. The ideas presented are common sense, but how often have we missed to boat. The ideas presented in the book I implemented much to my own joy. The result was a customized deployment of the Java Logging system which is simple to maintain and does not require external libraries.

It was at that point I realized the brilliance of the book and the pragmatic side of things. I re-read the book. As an architect, project manager, developer, and maintainer of complex software ecosystems, the ideas in the book provide a "pragmatic" common sense approach to handling situations. The book is a learning tool, one person's personal perspective on software design and deployment, and a reference. It is an all-in-one book.

This book provides a great tutorial on how to manage complex projects for the novice, and a gentle practical reminder to the seasoned architect/project manager.

The book is divided into 4 major sections: Stability, Capacity, General Design Issues, and Operations. The first two sections provide the basis for the remainder of the book. The Stability and Capacity sections have divided the topic into an explanation, followed by general design patterns and anti-patterns. It explains in enough detail how to implement good patterns and recognize bad ones.

The section on General Design covers items like Administration and Security. There is nothing earth shattering in these sections, but they do provide a basis for a "check list" of items to make sure you consider in your designs.

The final section on Operations is the one where you will make friends with your administrators and keep your sanity. The portions on designing for monitoring including logging will be your savior at 2:00 AM in the middle of a blizzard. The discussion on designing for the future does not get enough attention in our modern get it out the door now world. This may be the push you need to think about it.

This is a book to have on your bookshelf. Mine is full of tabs and post-it notes.